textproduct: Rapid City

KEY MESSAGES

- Scattered shra/isolated TS end early this evening over southwest half of CWA.

- Cold front drops through late tonight/Monday morning with gusty northerly winds behind it as well as some showers.

- Mean northwest flow aloft brings unsettled weather through next weekend.

DISCUSSION

(This Evening Through Sunday) Issued at 1203 PM MDT Sun May 3 2026

17z surface analysis had weak trough from the Big Horns into the NE panhandle. Trough reflection of compact shortwave over the Big Horns per water vapour loop. 0.5km visible satellite matinee depicted agitated CU/TCU field associated with these features. Few lightning strikes near the Big Horns with slowly increasing radar returns over the Black Hills. ~250J/kg SBCAPE out there, forecast to peak around 500J/kg per SPC HREF. Result will be scattered shra/isolated TS through early this evening over the southwest half of the CWA. Enough 0-6km bulk shear to help a storm if buoyancy were higher, but wouldn't be surprised to see a storm put out a 30-40kt wind gust given the 18z KUNR sounding.

After the precipitation ends early this evening, next upstream shortwave trough careens southward into the northern Plains late tonight/Monday morning pushing a cold front through the CWA. Decent pressure rises behind front with forecast soundings depicting well-mixed boundary layer late Monday morning into the afternoon hours. Result will be gusty northwest winds at times, especially from K2WX-KRCA where NBM probability of >45mph wind gusts is 40-70%. Have hoisted a Wind Advisory to account. Band of 800-600mb frontogenesis will support scattered showers potentially enhancing downward momentum transfer. Temperatures will be cooler/near guidance.

Mean northwest flow aloft continues for Tuesday through next weekend with a parade of shortwaves/surface fronts. Result will be isolated/scattered showers at times. Temperatures will be 5-10F below normal Tuesday/Wednesday, but then rise to 5-10F above normal for the weekend. Confidence is fairly high until next weekend when typical ensemble guidance spreads come into play.

AVIATION

(For the 00Z TAFS Through 00Z Monday Evening) Issued At 652 PM MDT Sun May 3 2026

Showers and thunderstorms have moved out of the region, leaving behind VFR conditions for this evening and overnight. A cold front is forecast to cross the region Monday morning, increasing winds out of the NW especially ramping up after 11z/5am and continuing through the day. There is the potential for showers as well, although confidence in direct impacts at either KRAP or KGCC is somewhat low with some differences between the CAMs. Overall potential seems greatest for now at KGCC in the 14-20z/8am-2pm window, thus have added a PROB30 -SHRA there with perhaps some clouds dipping just below VFR thresholds with that activity.

UNR WATCHES/WARNINGS/ADVISORIES

SD...Wind Advisory from 9 AM to 6 PM MDT Monday for SDZ001-002-012- 013-073-078. WY...None.